Recreational fire starting aid

ABSTRACT

An apparatus having a regulator fluidly connected to a nozzle by a fuel supply conduit can be fluidly connected to a source of liquefied fuel, such as liquefied petroleum gas. The apparatus can be used to initiate self-sustaining combustion of combustible materials in poor condition. The apparatus can be used to dispense a gaseous jet stream of the fuel through an air space and towards combustible materials for aspirating a portion of the air in the air space. The gaseous stream fuel contacts the combustible materials for mixing the gaseous fuel with air surrounding the combustible materials and with the portion of aspirated air, forming a flammable mixture. The flammable mixture can be automatically ignited by the heat of combustion provided by an open source of ignition adjacent the combustible materials.

CROSS REFERENCE OF RELATED APPLICATIONS

This application claims the benefits under 35 U.S.C 119(e) of U.S. Provisional Application Ser. No. 61/477,230, filed Apr. 20, 2011, which is incorporated fully herein by reference.

FIELD

Embodiments made herein are generally related to aids for initiating combustion of recreational fires including campfires and wood-burning fireplaces. More particularly, embodiments made herein relate to a method of initiating self-sustaining combustion of combustible materials in poor conditions.

BACKGROUND

When conditions for recreational fires are poor, starting a recreational fire can be difficult, which can lead to frustration for the user and loss of enjoyment of the activity. Campers are often seeking to initiate a campfire in poor weather conditions, which usually means that combustible materials, such as wood, are in poor condition, such as being wet, and difficult to ignite. Similarly, wet wood, or other combustible materials, is difficult to start for use in fire pits, barbeque fire grills and fireplaces. Herein, arrangements for the initiation and combustion of wood-like fuel in a recreational manner, such as for heat, ambience or cooking, are referred to collectively as a wood fire.

Use of flammable starter fluids are crude and can result in flare up and application to unsuitable areas, namely areas other than the location of the wood fire.

There is an ongoing need for a simple yet safe aid to initiating a recreational wood fire, particularly when the weather is poor and the wood or like fuel is in poor condition.

SUMMARY

Embodiments of the recreational fire starting aid can include a method for initiating self-sustaining combustion of combustible materials in poor condition. The method involves providing fuel as a gaseous jet stream towards an open ignition source adjacent a source of combustible materials. The gaseous jet stream of fuel, too rich and above an upper flammability limit of the fuel, will not ignite until the jet stream contacts the combustible materials and mixes with air surrounding the combustible materials for providing a flammable fuel/air mixture. The open source of ignition provides an ignition temperature sufficient to cause the flammable fuel/air mixture to automatically ignite and combust.

In a broad aspect, a method for initiating a self-sustaining combustion of combustible materials in an open air space involves providing a source of fuel, providing an open ignition source adjacent the combustible materials, regulating the fuel to discharge a generally coherent gaseous stream thereof through an air space, directing the gaseous stream of fuel towards the open source of ignition and combustible materials, contacting the combustible materials for mixing the gaseous fuel with air for forming a flammable mixture, igniting the flammable mixture with the open source of ignition, and continue directing the gaseous stream of fuel towards the combustible materials until combustion of the materials is self-sustaining.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a representative drawing of an embodiment of the present invention, illustrating the inability to ignite a jet stream of gaseous fuel;

FIG. 2 a representative drawing of an embodiment of the present invention, illustrating a jet stream of gaseous fuel being directed towards an open source of ignition and a pile of wet wood; and

FIG. 3 is a representative drawing of an embodiment of the present invention, illustrating a regulator fluidly connected to a fuel supply conduit having a nozzle attached thereto by a fitting.

DETAILED DESCRIPTION

Generally, embodiments of the disclosure supply a gaseous jet stream of fuel to an open source of ignition. Embodiments can comprise a nozzle, fluidly connected to a fuel supply, for directing the gaseous jet stream of fuel, which is outside its flammability limits. In combination with combustible materials, the gaseous jet stream of fuel mixes with surrounding air at the combustible materials to form a flammable fuel/air mixture which can be ignited automatically by the open source of ignition.

As commonly known to those skilled in the art, combustion is an exothermic reaction or oxidation of a fuel that produces heat and product gases. Reactant gases, such as fuel and oxygen, are allowed to mix, and when exposed to a source of ignition at a specific ignition temperature dependent on the type of fuel, automatic ignition or combustion of the fuel/air mixture commences.

Combustion achieves steady state, or is self-sustaining, when the fuel mixes with available oxygen to form a flammable mixture having a fuel/air ratio that is within concentration or flammability limits specific to the particular fuel used. Flammability limits are usually expressed in percent of fuel by volume. A lower flammable limit (LFL), usually describes the concentration or leanest mixture of fuel and air that is ignitable. An upper flammable limit (UFL) describes the concentration or richest mixture that is ignitable. If there is too little fuel or too lean, the fuel will not combust. Conversely, if there is too much fuel or too rich, the fuel will also not combust.

Embodiments herein can dispense fuel in gaseous jet stream from a nozzle without consideration of the usual air mixing means conventionally used to sustain a stable flame or combustion. That is, the gaseous fuel is dispensed above the UFL for that particular fuel. Accordingly, the fuel exits a nozzle and when projected as a jet stream into an unrestricted air space, is too rich and will not sustain a flame without lifting off or blowing out. In other words, the nozzle conditions are insufficient to maintain a stable flame. That is, the flammable fuel/air mixture is outside the flammability limits of the fuel being dispensed.

As shown in FIG. 2, conditions to maintain combustion are achieved in combination with a wood fire. A gaseous jet stream of fuel, such as liquefied petroleum gas (LPG), commonly known as propane, can be directed from a distance at an open source of ignition adjacent combustible materials, such as a pile of wet difficult-to-start fuel. The fuel is arranged or located in a surrounding air. The gaseous jet stream of fuel mixes sufficiently with air at the pile of difficult-to-start fuel for initiating and sustaining combustion.

The gaseous jet stream of propane can be directed towards the pile of wood at a sufficient velocity to aspirate a portion of the air surrounding the jet stream. The aspirated air is carried along with the gaseous jet stream towards the pile of wood for mixing thereat. As the directed jet stream contacts the pile of wood, the velocity of the jet stream is reduced to allow the gaseous fuel to sufficiently mix with the air surrounding the pile of wood and with the air aspirated by the jet stream and carried thereto, such that the flammable fuel/air mixture is within the flammability limits of the particular fuel. For example, according to the Material Safety Data Sheet (MSDS) for propane, the lower flammability limit is about 2.4% while the upper flammability limit is about 9.5%. The open source of ignition, such as an open flame, provides sufficient ignition temperature to cause automatic ignition of the flammable mixture at the pile of wood.

With reference to FIG. 1, generally, an apparatus 10 for directing a jet stream of gaseous fuel 20 can comprise a nozzle 30, a gas regulator 40, and a fuel supply conduit 50 which spaces the nozzle 30 from the regulator 40. The gas regulator 40 can be adapted for connection, usually threadably, to a fuel source 60, such as a 16.4 oz, non-refillable, pressurized propane cylinder manufactured by Coleman® (a registered trademark of The Coleman Company, Inc., of Wichita, Kans., USA) and available at most retailers selling outdoor equipment.

As shown in FIG. 2, the regulator 40 can be used to regulate propane gas from the propane cylinder 60 to discharge a coherent jet stream of gaseous propane 20 from the cylinder 60, through the fuel supply conduit 50 and be directed towards an open source of ignition 70 and combustible materials 80 by the nozzle 30.

The propane cylinder 60 is typically carried and manipulated by an end user. The user and propane cylinder 60 can be maintained in a safe environment by spacing the cylinder 60 and the user sufficiently from the open flame, firstly by the length of the fuel supply conduit 50 and secondly, by the user spacing the apparatus 10, and in particular the nozzle 30, from the open flame.

In an embodiment, the regulator 40 can be a single stage regulator or those regulators which are limited to small portable appliances and outdoor cooking appliances. The regulator 40 can utilize a Type I relief valve which has a limited capacity of operating between about 0.7 psig and about 1.2 psig (about 18.7″ and about 33″ water column [w.c.], respectively). An example of a gas regulator can be a low pressure gas regulator typically used for recreational use such as propane canisters for barbeques, lanterns and the like.

In an example of an embodiment, the supply conduit 50 can be about 15 inches in length and the nozzle 30, having a nozzle opening of about 1/32 inches, can be spaced in the order of about 6 inches from a wood fire or combustible materials 80. In an embodiment, and as shown in FIG. 3, the conduit 50 can be a stainless steel tubing or pipe, about ¼″ in diameter, and can be fit with a fitting 90 at a discharge end 100 of the conduit 50 for replaceably receiving the nozzle 30. Applicant notes that stainless steel is a good choice for manufacturing the conduit 50 as stainless steel is a poor thermal conductor and minimizes conduction of heat from the fire towards the regulator 40 and operator. Further, the pressure drop and vaporization of fuel as it leaves the regulator cools the conduit 50 as the gaseous fuel is conducted to the nozzle 30.

An example of an embodiment is set forth in FIGS. 1 to 3, illustrating the propane cylinder 60, the regulator 40, the conduit 50, fitting 90 and nozzle 30. As shown in FIG. 1, the fuel is dispensed from the nozzle 30 as a gaseous jet stream 20. However, the jet stream 20 is too rich and beyond the upper flammability limit of the fuel, and attempts to ignite the gaseous jet stream 20 with a lighter will result in repeated flame out.

With reference to FIG. 2, the jet stream of gaseous fuel 20 aspirates air surrounding the jet stream 20 with it for mixing at the wood fire. Starter fuel or an open source of ignition, such as paper, is already alight adjacent the difficult-to-start fuel using a lighter, match, or other source of ignition. Gaseous fuel, mixing with surrounding air at the wood fire, burns and provides the extra impetus to initiate a self-sustaining wood combustion at the wood fire.

Once starter wood-like fuel, such as kindling or paper, is burning, the spacing of the nozzle 30 away from the combustible materials 80 is not critical, the jet stream of fuel 20 aspirating air with the fuel into the wood fire and the starter fuel acting as a continual ignition source. The gaseous fuel stream 20 can then be turned off after which the wood fire continues, generating sufficient heat to dry any wet wood and continue self-sustaining combustion.

FIG. 3 is a close up and partial view of the regulator 40, conduit 50, fitting 90 and nozzle 30. In an embodiment, a suitable nozzle 30 is sized for about 10,000 BTU/hr.

In Operation

Combustible materials in poor condition, such as wet wood, can be placed in a pile. A regulator can be fluidly connected and secured to a source of fuel. In this particular case, the source of fuel can be commercially available propane stored in pressurized cylinders. A fuel supply conduit, having a nozzle fluidly connected thereto at one end, can be threadably or otherwise fluidly connected to the regulator and the fuel supply.

An open source of ignition is placed adjacent to the combustible materials for providing sufficient heat to reach the required ignition temperature for automatically igniting the fuel source. For example, propane has an ignition temperature of about 940° F. Accordingly, examples of an open source of ignition may include, but is not limited to, dry kindling lit on fire by way of a match or lighter, or other forms of an open flame.

With an open source of ignition adjacent the pile of wet wood, an user can regulate the propane cylinder to discharge a generally coherent jet stream of gaseous propane through the air space between the user and the pile of wet wood. The jet stream is discharged at a velocity sufficient to aspirate air from a portion of the air space into the jet stream and the jet stream is directed towards the open source of ignition, carrying the aspirated therewith. The user can be distanced sufficiently away from the pile of wood such that the jet stream of gaseous propane remains above its upper flammability limit (about 9.6% for propane).

When the jet stream of gaseous propane contacts the pile of wood, the velocity of the jet stream is reduced and the jet stream is interrupted sufficiently to allow the gaseous fuel to disperse and mix with the air surrounding the pile of wood and with the air aspirated thereto for forming a flammable mixture having a fuel/air ratio within the flammability limits of the fuel. The open source of ignition provides sufficient heat to reach the ignition temperature (of about 940° F. for propane) for enabling automatic ignition of the flammable mixture.

The jet stream of fuel is continuously directed towards the pile of wet wood and the open source of ignition for providing continuous heat of combustion to dry the wet wood until such time as at least some of the wet wood is sufficiently dry enough to self-sustain combustion.

In an embodiment, the pile of wet wood can be erected into a teepee configuration having an open air space at a base thereof for circulation of surrounding air thereabout. The open flame can be placed within the open air space at the base and the jet stream of fuel, such as propane, can be directed at the open flame until such time the teepee of wood has a self-sustaining fire. 

1. A method for initiating a self-sustaining combustion of combustible materials, comprising: providing a source of fuel located in surrounding air; providing an open source of ignition adjacent the combustible materials; regulating the fuel to discharge a generally coherent stream of gaseous fuel through an air space between the combustible materials and the source of fuel; directing the stream of gaseous fuel towards the combustible materials at a distance from the combustible materials that the stream of gaseous fuel in the air space remains above an upper flammability limit of the fuel; contacting the stream with the combustible materials for interrupting the stream and mixing the gaseous fuel with the surrounding air forming a flammable mixture; igniting the flammable mixture with the open ignition source for imparting heat of combustion into the combustible materials; and continuing directing the stream towards the combustible materials until combustion of the combustible materials is self-sustaining.
 2. The method of claim 1 wherein the directing the stream towards the combustible materials further comprises: aspirating a portion of the air from the air space with the stream; and dispersing the stream of gaseous fuel and aspirated air through contact with the combustible materials for mixing the gaseous fuel, the aspirate fuel, and air and forming the flammable mixture adjacent the combustible materials.
 3. The method of claim 1 wherein the directing the stream towards the combustible materials further comprises: discharging the regulated stream of gaseous fuel through a nozzle.
 4. The method of claim 1 wherein the regulating the fuel further comprises: providing a single stage regulator fluidly connected to the source of fuel for discharging gaseous fuel at a pressure of about 0.7 psig to about 1.2 psig.
 5. The method of claim 4 wherein the discharging of a generally coherent stream of gaseous fuel through the air space further comprises: providing a conduit between the regulator and the nozzle; directing the gaseous fuel through the conduit; and discharging the gaseous fuel through the nozzle.
 6. The method of claim 1 wherein the providing of an open ignition source comprises providing an open flame.
 7. The method of claim 1 wherein the fuel is propane and the open source of ignition provides an ignition temperature at least about 940° F.
 8. The method of claim 1 wherein the fuel is propane and the coherent stream of gaseous fuel is above about 9.6% propane in air.
 9. A method of building a campfire in an open air space comprising: erecting a teepee of wood in the open air space for circulation of surrounding air about a base of the teepee, the wood being combustible materials; initiating self-sustaining combustion of the combustible materials using the method of claim
 1. 